Presentations to an audience are frequently made with the assistance of images projected onto a front or rear projection screen. With either type of screen it is necessary at an appropriate time for the presenter to change to the next image. Buttons on a computer keyboard are designated to advance a frame or to back up a frame. A presenter may use an off-stage assistant that brings up the next image frame at his signal, or spoken request, “Next slide please”.
Effort has been made to eliminate the keyboard, verbal request, hand signals and gestures. Cordless remote controls can be used to advance to the next image, or return to the previously projected image. In applications where image changes occur rapidly (near real time) it is not practical to use a remote control for switching to the next image.
As a means of increasing alert attention and holding the interest of an audience, iSkia™, a device produced by iMatte Inc. U.S. Pat. No. 6,361,173, selectively inhibits the projected image in the silhouette area of a presenter. The presenter may then come out from behind the podium and walk out in front of the screen. He may look directly at his audience without being blinded by the projector. He may walk across the stage in front of the screen and point directly to elements in the projected image.
The above invention generates a matte silhouette of the presenter for identifying those pixels to inhibit. This matte can also be used to locate the presenter's screen position. A change in the presenter's position with respect to the display screen, from a first position to a second position may be used to generate a control signal.